有色矿冶区污染蔬菜土壤中重金属活性

Availability of heavy metals in contaminated vegetable soils from the vicinity of non-ferrous metals mining and smelting areas

从湖南省长沙、株洲、衡阳和郴州地区典型有色金属矿冶区采集土壤和蔬菜样品,采用BCR法连续提取污染土壤中重金属不同组分,结合土壤中粘土矿物相、土壤和蔬菜重金属全量分析污染土壤重金属活性,并探讨其潜在环境风险。研究结果表明,土壤中Cd,Cu和Pb的可提取态含量与其在土壤中含量之比分别高达61.71%,43.14%和48.84%;土壤Cd的活性组分以酸可提取态为主,As,Cu和Pb以可还原态为主,Zn以酸可提取态和可还原态为主;土壤重金属尤其是As,Cd,Cu,Pb和Zn有效性组分之间存在明显的复合污染效应;土壤Cd,Cu和Zn可提取态含量与蔬菜Cd,Zn和Cu含量之间均存在显著正相关关系。

The samples of soils and vegetables were collected from the vicinity of non-ferrous metals mining and smelting areas in the districts of Changsha, Zhuzhou, Hengyang and Chenzhou of Hunan Province. The fractions of heavy metals in soils were analyzed by three-stage BCR sequential extraction procedure, the characteristics of clay mineral in soils and the contents of heavy metals in soils and vegetables were determined in order to elucidate the availability and potential environmental risk of metal fractions in contaminated soils. The ratios of total extractable fraction content to the total content for Cd, Cu and Pb are 61.71%, 43.14% and 48.84%, respectively. The active fractions of Cd in soils mainly exist as acid-extractable forms, those of As, Cu and Pb mainly exist as reducible forms, and those of Zn mainly exist as acid-extractable and reducible forms. The results show that the combined pollution for active fractions of As, Cd, Cu, Pb and Zn in soils are significant, and the significant relationships between total extractable contents of Cd, Cu and Zn in soils and total contents of those in vegetables are also found through clustering analysis and correlative analysis.